RNA from extinct Tasmanian tiger recovered for the first time

By D.W.

22 Sep 2023, 00:40 AM EDT

The Tasmanian tiger, also known as the thylacine, was a carnivorous marsupial similar in size to a dog, characterized by its stripes on its back.

This species used to live on the Australian continent and nearby islands, where it played a crucial role as a top predator in its ecosystem, hunting prey such as kangaroos and other animals. Tragically, due to human influence, this species has become extinct.

Despite its extinction, scientists have not stopped learning about the Tasmanian tiger. In a scientific first, researchers recently announced that they were able to extract RNA, a genetic material present in all living cells that has structural similarities to DNA, from skin and muscle samples of a stuffed Tasmanian tiger dating back to 1891 and found in a museum in Stockholm.

In recent years, scientists have managed to extract DNA from ancient animals and plants, including species that lived more than two million years ago. However, this study marks the first time that RNA, a genetic molecule less stable than DNA, has been recovered from an extinct species.

Recreate extinct species?

Although recreating extinct species is not the primary goal of this research, the ability to extract, sequence, and analyze ancient RNA could boost the efforts of other scientists working on recreating extinct species. Additionally, recovering RNA from ancient viruses could help understand the causes of past pandemics.

Both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are fundamental molecules in cell biology. DNA is a double-stranded molecule that contains the genetic code of an organism and is responsible for genetic inheritance.

On the other hand, RNA is a single-stranded molecule that carries genetic information from DNA and uses it to synthesize essential proteins and regulate cellular metabolism.

“RNA sequencing allows us to get an idea of ​​the real biology and the regulation of the metabolism that took place in the cells and tissues of Tasmanian tigers before they became extinct,” says geneticist and bioinformatician Emilio Mármol Sánchez, from the Center of Paleogenetics and SciLifeLab of Sweden, lead author of the study published in the journal Genome Research.

“If we want to understand extinct species, we need to understand what genetic complements they have and also what the genes were doing and which ones were active,” said geneticist and study co-author Marc Friedländer of Stockholm University and SciLifeLab.

The Tasmanian tiger resembled a wolf, apart from the tiger-shaped stripes on its back. The arrival of man in Australia about 50,000 years ago led to massive population loss. The arrival of European colonizers in the 18th century marked the end of the populations that remained concentrated on the island of Tasmania, and later a reward was imposed on them after declaring them a danger to livestock. The last known Tasmanian tiger succumbed in a zoo on the island in 1936.

“The story of the disappearance of the thylacine is, in a certain sense, one of the most documented and proven extinction episodes. Unfortunately, Tasmanian tigers were declared protected only two months before the last known specimen died in captivity, too late to save them from extinction,” Mármol said.

Private “de-extinction” initiatives have been launched to revive certain extinct species, such as the Tasmanian tiger, the dodo and the woolly mammoth.

“While we remain skeptical about the possibility of truly recreating an extinct species by gene editing living relatives of existing animals – and the time frame to reach an endpoint could be underestimated – we advocate for further research into the biology of these animals.” extinct animals,” said Mármol.

Keep reading:
· Lost remains of the last Tasmanian tiger from 1936 are found in a museum closet
· Scientists seek to genetically “resurrect” the extinct Tasmanian tiger